This invention relates to an image recording device and more particularly to an image recording device which performs image recording through formation of a latent image on a photo-sensitive composition.
There has been known such an image recording device in which a latent image formed on a circumferential surface of a photo-conductive drum is developed to a visible image with charged particles called toners, and the resultant toner image formed on the drum is then transferred and set on a plain paper for recording the image thereon. In recent years, image recording devices of this type are becoming widely available as laser printers where writing a latent image on the photo-conductive drum is carried out by a laser scanner, and as electronic copying machines where a latet image is formed with light reflections from a text or image to be copied.
In the meantime, it has been proposed, as disclosed in the U.S. Ser. No. 50,313 filed on May 14, 1987, to obtain a longer service life of the photo-sensitive composition as well as added facilities of printing and copying (e.g. in full-color) through combination of the advantages of the latent image formation scheme as mentioned above with the use of the photo and pressure sensitive paper. In more particular, the image recording device ensures a longer life of the photo-sensitive composition by developing the latent image formed on the photo-sensitive composition with light-shield materials, then transferring the developed image onto a transparent film and exposing the photo and pressure sensitive paper through this transparent film instead of the photo-sensitive composition, while providing color printing and copying by repeating this procedure for every primary color.
While the image recording device utilizing the photo and pressure sensitive paper has brought the above advantages, further improvements have been desired. That is, although an important feature of the image recording device utilizing the photo and pressure sensitive paper resides in provision of color printing and copying with practical cost, device and arrangement, if one wants to have a simple black and white print or copy in the above image recording device, exposure to three primary colors of yellow, magenta and cyan is still to be done to provide "black" as the result of subtractive process. This has resulted in a problem that providing a monochrom image has taken the same length of time as for color image. Moreover, the time required for recording a monochrom image becomes longer than the prior ways because exposure takes place after transferring the image onto the transparent film, whereupon the film must be brought to a complete stop in the above image recording device. So this problem has been too serious to be overlooked when a simple black and white image is enough for the purpose.